Endoscopic procedures gain access to the inside of a human or veterinary body by using a cutting instrument to pierce or puncture bodily tissues (i.e., skin, muscles, membranes, or the like), and then a narrow cannula is inserted through the puncture wound as a guideway for access to the body interior. The cannula is narrow as the area in which the surgeon must perform procedures incorporating endoscopic medical instrumentation is smaller than that normally encountered when conventional surgical techniques are employed. As a result, endoscopic medical procedures are minimally invasive and leave minimal scarring for the patient.
More particularly, in endoscopic procedures, various implements are inserted through the skin and body wall into the body, wherein surgical procedures are to be undertaken. The interior operating site is "visualized" by employing an endoscope or viewing port that also extends into the body. While the surgeon may view the interior of the body directly through the endoscope, usually, the endoscope is connected to a camera and television monitor that presents a magnified view of the body interior for the surgeon to view. By viewing the interior, the surgeon can conduct operative procedures by employing different narrow implements.
To allow for better visualization of the body interior and easier access to the operative site, an insufflation procedure may possibly be employed depending on the specific operative site. During insufflation, a gas, typically carbon dioxide, is injected into the body to initiate enlargement of the area where surgery is to be performed and maintain that area in enlarged form. To achieve insufflation, a first puncture or stab wound is made and then a narrow pneumoperitoneum insufflation needle (called a Veress-type needle) is used to puncture the body wall and the gas is introduced through the needle. Insufflation is especially used when the surgical area is the abdominal cavity, and the endoscopic procedure is a laparoscopic procedure. However, it is to be kept in mind that endoscopic procedures are increasingly being employed for surgery in various other body areas, such as for arthroscopic surgery on joints or for insertion of breast implants. One method of placing these implants is by way of the bikini line below the patient's waist so that any scars from the breast enlargement surgery are at the bikini line instead of at the breast area.
After a pneumoperitoneum is adequately established (or in the event of surgery such as on a knuckle joint where there is no pneumoperitoneum) and the endoscope is in place, additional puncture or stab wounds may be made for the narrow endoscopic implements. A tubular sheath (commonly called a cannula) is inserted through the puncture wound while a cutting instrument (commonly called a trocar) is disposed inside of the sheath with the cutting edge of the trocar protruding past the end of the sheath. The cannula and trocar are gently advanced into the body under direct visualization. The sharp cutting tip of the trocar cuts the way for the cannula to be advanced into the body, and sometimes only a cannula (without any trocar) having a sharp cutting tip for advancement into the body is used.
The sheath is left in place (advanced through the puncture wound in the body) in order to gain access within the body. Thus, the sheath keeps the puncture wound open, and then the trocar (if one has been used) is removed so that now the sheath provides an access channel or guideway for narrow endoscopic implements other than a trocar to be inserted through the tubular hole of the sheath so that surgery can be performed inside the body.
For instance, forceps (commonly called graspers) may be placed through the sheath so that the bowel may be grasped, the liver retracted, or the peritoneal surface grasped with the working end of the forceps. Next, the forceps may be removed from the sheath and a cautery placed therethrough so that micro-hemostasis can be achieved using electrocautery.
As noted hereinabove, endoscopic medical implements are small so that instrumentation is smaller than that encountered with conventional surgical techniques. As a result, endoscopic procedures result in significantly less trauma than that from conventional invasive surgery and also lead to typically much shorter recovery time for the patient. Of course, the smaller the endoscopic implements are, then the less invasive the endoscopic procedure is.
For current commercial implements, the elongated, cylindrical portion of an endoscopic medical implement is typically about 5 mm to about 10 mm in cross-sectional diameter, and the tubular cannula to provide guidance therefore typically has an internal diameter of about 11 mm in cross-section. Such endoscopic medical implements are made of plastic or metal, and a limiting factor in the smallness of the diameter has been found because if they are manufactured too thin and narrow, they would be fragile and would easily snap or break inside of the body, leaving the working end of the implement inside of the body. Then, conventional invasive surgery with a large cut area would have to be performed in order to remove from the body the working end that had broken off of the endoscopic medical implement.
To date, no satisfactory way has been found to employ extremely small diameter endoscopic implements and thus make endoscopic procedures even less invasive than they currently are without having the danger of the working end of the implement breaking off inside of the body. Nevertheless, the following patents are of general background interest vis-a-vis endoscopic implements and/or sheaths (cannulas) for insertion of implements therethrough and into the body either through a puncture wound or a body orifice.
U.S. Pat. No. 5,355,871 to Hurley et al., assignors to Dexide, Inc., involves a cylindrical housing as a guideway for an endoscopic surgical instrument. The instrument is concentrically disposed interior of the housing and movable between first and second positions. The housing includes a flexible, dome-like portion that is located for engagement by the thumb and forefinger of a human operator and overlies a portion of the endoscopic surgical instrument. As the flexible portion is grasped and compressed with the thumb and forefinger, the endoscopic surgical instrument is held in place inside of the cylindrical housing. A drawback is that if the human operator should inadvertently loosen the grip of the thumb and forefinger, the endoscopic surgical instrument will slide and move to a different position inside of the cylindrical housing.
U.S. Pat. No. 5,364,365 to Wortrich, assignor to Surgin Surgical Instrumentation, Inc., discloses an elongated surgical instrument for penetrating into a body cavity. The instrument has an obturator with a cutting cannula. The obturator is spring-mounted so that it will retract within the cannula when the cannula encounters a body wall, but also so that it will move to an extended distal position inside the body cavity. The obturator can be locked in an axial position when it is in the extended distal position so that the instrument can be used in a surgical procedure without danger of cutting internal tissue or organs. Thus, the obturator is a safety device that facilitates use of instruments during laparoscopic surgery.
Various needle assemblies that include an introducer needle having another member movable therein between different positions are shown in U.S. Pat. No. 5,312,375 to Gurmarnik (no assignee); U.S. Pat. No. 5,292,310 to Yoon (no assignee); and U.S. Pat. No. 5,057,085 to Kopans, assignor to Medical Device Technologies, Inc. In the patent to Gurmarnik, the other member is a spinal needle. In the patent to Yoon, the other member is a safety probe. In the patent to Kopans, the other member is a trocar. Each of the devices in these three patents is provided with a set screw for locking in place the member that moves from a first position to a second position within the introducing needle.
Also, of some relevance vis-a-vis an assembly with an outer sheath and a removable instrument located therewithin is U.S. Pat. No. 4,461,280 to Baumgartner (no assignee). This patent involves a method for medical treatment of the prostate area with a urethrally inserted apparatus assembly. The apparatus assembly has an outer sheath and a removable obturator located within the sheath during insertion of the assembly into the urinary tract by way of the urethral orifice in the penis. One end of the sheath is configured to retain the tip of the obturator, and the other end of the sheath is rigidly retained in a mounting member and extends through the mounting member and a locking member of conventional construction. The mounting member retains the locking member so that it will rotate relative to the mounting member in order to align slots for receiving the obturator. When the obturator is inserted into the sheath, projecting pins engage those slots and the locking member can be rotated to retain the obturator securely in position. Once the sheath is in position in the selected area, the obturator is removed from the sheath and a sampling implement having a harpoon-blade working end is inserted into and through the sheath to a location adjacent the selected area of the prostate. The harpoon end has both a tip (which is used to puncture the tissue to be sampled) and a pocket behind the tip (which is used for collecting the tissue sample).